The major objective of this research program is to gain new insights into the molecular and cell biological mechanisms underlying the production and actions of insulin and related peptide hormones of the islets of Langerhans, including their genetic basis, evolution origins and disorders which may contribute to the pathophysiology of diabetes and/or other diseases in man. New projects and extensions of previous work are proposed as follows: (1) Studies on mutant human insulin genes giving rise to abnormal proinsulins or insulins having altered properties affecting their biosynthesis, transport and sorting and/or their receptor binding affinities, including improved methods for their detection and for evaluating their functional consequences via expression in vitro or in transgenic animals. (2) Studies on the role of metal ions such as zinc and calcium in the formation, maturation and stability of insulin secretory granules. (3) Development of new methods for the identification and study of prohormonal processing enzymes. (4) Studies on the biosynthesis and properties of modified and hybrid proinsulin molecules. (5) Studies on ion channels and receptors of beta cells which may play a role in regulating the secretion of insulin. (6) Studies on the biosynthesis and secretion of other islet amyloid peptide, a new beta cell product that may play a role in the pathogenesis of type II diabetes. (7) Studies on the differentiation and growth of islet cells using clonally derived insulinoma lines having the properties of pluripotent stem cells. (8) Studies on the structure of the insulin receptor with special emphasis on the molecular mechanisms of insulin binding and the conformational changes associated with transmembrane signalling. (9) Studies on mutations in the insulin receptor in man that influence its biosynthesis and proteolytic processing and are associated with severe insulin-resistant diabetes. (10) Comparative studies on the evolution of the insulin superfamily of hormones and their receptor mechanisms. These studies should all contribute to improving our understanding of the genetic, evolutionary, developmental and cellular biochemical mechanisms underlying islet hormone production and action.